Supercharger for aircraft engines



H. ALFARO SUPERCHARGER FOR AIRCRAFT ENGINES Dec. 23, 1941.

Filed Dec. 16, 1939 `3 Sheets-Sheet l [III/lll a a .b H 7 8 Z nmummw 0 Z n o MM 4 L z INVENToR HERACLIO ALFARO Bfw Z ATTORNEYS Dec. `23, 1941. H, ALFARQ 2,267,437

SUPERCHARGER FO AIRCRAFT ENGINES Filed Dec. 16, 1959 3 sheets-sheet 2 /8 l5@ f4 zz Z0 F.' w O I u Z5 5f.- Z/ 'Z7 u /5a /0 /4 /9 Z5 g l o 1 y 55 HERAcLlo ALFARO E' a Qfff Dec. 23, 1941. H.4 'ALFARO 2,267,437

, SUPERCHARGER FOR AIRCRAFT ENGINES Filed Dec. 16, 1959 5 sheets-sheet 5 INVENTOR H E RACLIO ALFARO M# ,f ATTORNEY Patented Dec. A2e., 1941 UNITED STATES PATENT OFFICE SUPERHARGER FOR AIRCRAFT ENGINES Heraclio Alfaro, Boston, Mass. Application December' 16, 1939, Serial No. 309,509

(c1. 12s-51) t ously- 'contrlled by a pressure-sensitive means;

. 29 claims.

This invention relates to internal combustion engines of the two-stroke cycle type, and more particularly to means for improving the performance of supercharged two-stroke cycle'en gines used 'in connection with aircraft.

The power of an internal combustion engine depends uponv the weight of air it consumes per unit of time. If the weight of the air is lower per unit of volume than at sea levell the power of aV conventional internal combustion engine drops in proportion to the drop' in atmospheric pressure at high altitudes. A To avoid this disadvantage, many engines are equipped with superchargers or means to' compress the air previous to reaching the cylinders. It is diicult to supercharge vengines of the two-stroke cycle type because of the fact that the air is admitted to the cylinder when both the inlet and the exhaust ports are open. Since the. exhaust is directly connected to the atmosphere it is diilicult to charge the cylinder with air at-a pressure higher than that of the surrounding atmosphere.

The present invention has forits object to increase the power attainable by a two-stroke cycle aircraft engine at high altitudes.

In my invention I take ladvantage of the .change of atmospheric pressure with altitude to automatically control the supercharging of two stroke cycle engines so as to obtain satisfactory supercharging at altitudes much above sea level.

A further object of the invention is to maintain substantially constant powerv at varying altitudes above sea level.

A further object of the invention is to provide means for regulating the fuel feed in such a way as to maintain the proper fuel-air ratio' above a predetermined altitude. n

With the above and other objects in view, the

invention may be said to comprise the device as illustrated in the accompanying drawings hereinafter described and particularly set forth in the appended claims, together with suchvariations and modifications thereof as will be apparent to one skilled in the art to which the invention appertains. Reference should ingdrawingsforming a part of this specification, in which: y

Figure 1 .is a diagrammatic sectional view showing the control device of the present invention applied to a cylinder of a two-stroke cycle engine; i

Fig. 2 is a view similar to Fig. ll, showing a modified form of the invention in which valves in the inlet and exhaust conduits are simultanebe had to the *accompany Fig. 3 is a diagrammaticsectional view similar to Fig. 1, showing a further modification in' 4the air inlet controlling valve iscontrolled by a separate pressure-sensitive device;

Fig. 6 is a diagrammatic sectional view showf ing a' further modification in which a single pressure controlled operating device. simultane- `ously actuates the air inlet, exhaust control 4valves and the airlpump, and'also controls the .fuel pump above a predetermined` altitude; and

Fig. '7 shows an axial section through the power actuated: pressure controlled actuator shown in Fig. 6;

Fig. 8 is a perspective View showing a modined forni of pressuresensitive power actuated control device;

Fig. 9 'is an-axial section taken on the line indicated at 9-,9 of Fig. 8: l

FIS. L10 is'a transverse section takenon the line indicated at IU-III in Fig; 9;

Fig. 11 is a transverse section taken on the line indicated at I I-'I I in Fig. 9;

Fig. 12 shows the controlling device of the present invention applied to the engine of an aeroplane; and

Fig,'13 is a sectional view of the change speed driving means for the air pump. In the accompanying drawings, the cylinder I of a two-cycle double opposed piston internal combustion engine is shown, the cylinder I being provided with inlet ports '2 and exhaust ports proximity midway between the ends of the cylinder tothe positions shown in the drawings in which the pistons I and I have moved outwardlyA past the inlet and exhaust ports 2 and 3 to Aopen the same. lThe reciprocating motion of the pistons l and 5` may be effected by any suitable means such as connecting rods, swash plates, end cams, or other means well known in the art. The engine may b e ofthe compression-ignition type or of the spark ignition type. If ofl the spark ignition type, suitable spark plugs 0 may be provided for igniting the charge. Fuel may be mixed with the air fed to a cylinder through the inlet ports 2, or it may be directly injected into the cylinder. As herein shown, fuel is delivered into the central portion of the cylinder through an injector nozzle 'I. Air is delivered into the cylinder through a pipe 8 by means of pump 9. The pipe 8 may be throttled by means of alvalve I 0 as shown in Figs. 2, 3, 5, and 6. The exhaust ports 3 communicate with a pipe II which may be throttled by means of a valve I2. In multicylinder engines the inlet pipe 8 and exhaust pipe II are preferably connected to suitable manifolds which communicate with all of the cylinders as shown in Fig. 12. In order to enable the pump 3 to deliver an equal weight of air at all times Ato the cylinder I regardless of' atmospheric pressure, means is provided to automatically control the position of the exhaust throttle valve I2 by means of an actuating device which is sensitive to changes in atmospheric pressure. As shown in Figs; 1, 2, 3, and 5, the actuator for the throttle valve I2 is in the form of a bellows I3 which is sealed and contains air at a suitable pressure so that it is contracted or expanded by an increase or decrease in atmospheric pressure acting upon the exterior thereof, one end of the bellows being attached to a stationary support and the opposite end of the bellows being movable. The pressure of the atmosphere tending to collapse the bellows may be resisted by suitable means such as a spring I4 shown attached at one end to the movable-end of the bellows and at its opposite end to a stationary member such as the pipe I I. When there is a decrease in atmospheric pressure such as occurs with an increase in altitude, the movable end of the bellows I3 is moved outwardly by the spring I4 and actuates the valve I2 through a connecting rod I5 toward closed position to throttle the exhaust. Throughout a considerable range oi altitudes, air may be supplied to the engine at a substantially constant pressure by the pump 9 through the pipe 8 regardless of the altitude at which the engine may be operating. At sea level the pressure of the air supplied through the pipe 8 may be only slightly above atmospheric pressure. At sea level the bellows I3 is compressed by atmospheric pressure and is collapsed sufiiciently in opposition to the spring I4 to maintain the valve I2 in substantially open position. As the altitude of the aircraft increases, the bellows I3 is expanded due to the pull of the spring I4 against the lesser atmospheric pressure 'and partly closes the throttle valve I2, the valve I2 approaching closed` position as the altitude increases. Bellows I3 and the spring I4 should be so adjusted as to maintain a substantially constant pressure in the cylinder during the charging operation regardless of atmospheric pressure. If the valve I2 were to remain entirely open, pressure of the air within the cylinder at the beginning of the inward stroke of the piston would not be substantially higher than the pressure of the surrounding atmosphere at the altitude at which the 'engine is operating, and at the higher altitudes there would be a substantial decrease in the power of the engine.

valve in such manner as tov restrict the exhaust By controlling the exhaust throttle at which the cylinder is charged at sea level, so that the power of the engine is maintained.

Any suitable means may be employed for controlling the position of the throttle valve I2 by the pressure of the surrounding atmosphere. The pressure-sensitive device controlling the valve I2 may be in the form of a bellows I3 such as shown in Figs. 1, 2, 3, and 5 which serves as a direct actuator for the valve, but, if desired, the pressure-sensitive element may serve as a control for a power actuated operating device as shown in Figs. 6 and 7, in which the actuating means, indicated generally by the numeral I'I, is a power actuated device controlled by a pressure sensitive element such as a bellows.

The pressure-sensitive means may advantageously control the air inlet valve I0 as well as the exhaust controlling valve I2. In Fig. 2 of the drawings the valve I2 is shown connected to the valve I 0 by means of a rod I6 which causes the valve I0 to be moved simultaneously with the valve I2, the position of the valve I0 being opposite that of the valve I2 so that as the exhaust is throttled the inlet is unthrottled, the verb forml "unthrottle being used herein to express the reversal of the throttling action. The valve I0 is preferably maintained partly closed at sea level and at the lower altitudes to avoid excessive pressure in the charge of air delivered to the cylinder, but as the altitude is increased the valve III is gradually opened, and the connections may be so arranged that the valve I0 is wholly opened at a predetermined altitude.

As shown in Fig. 2, the valve actuating rod I5 is connected to .a lever I5a pivoted at one end to the movable head of the bellows I3 and at its opposite end to a normally fixed rod I5b. 'Ihe rod I5b may be normally held against movement by friction andI may be actuated by means of a lever I5c so that the desired adjustments of the valves may be made manually in the event that the pressure-sensitive device should for any reason become ineffective.

It is apparent that equivalent results can be .4 obtained by operating the valve I0 by means of a separate bellows I3a as shown in Fig. 3, the valve I0 being connected directly toa rod I5a and the bellows being provided with a spring I4a, the connection being such that as the bellows is moved outwardly by the spring I4a, the valve I0 is moved toward open position.

In some instances it may be desirable to regulate the fuel feed in addition to the air Inlet and exhaust. As shown in Figs. 3, 4, 5, and 6 of the drawings, a suitable fuel pump I8 is connected by a pipe I3 with the injector nozzle 'I for delivering charges of fuel to the cylinder I. 'I'he pump I3 may be provided with a suitable movable regulator 20 which controls the volume of the charges of fuel delivered through the pipe I9. The regulator 23 may be of any suitable type and may be actuated by a suitable lever 2|, one end of which is connected by a link 22 to the regulator 20, the opposite end of the lever 2l being pivoted either to the movable part of the bellows I3, as shown in Fig. 5, or the movable part of a separate bellows I3b, as shown in Fig. 3." 'I'he lever 2| is pivoted intermediate its ends at 23 to 'a supporting member 24 which is normally stationary so that the lever 2I is rocked about its pivot 23 when the bellows I3 or I3b is expanded or contracted. A movement of the bellows imparts a proportional movement to the regulator 23 and increases or decreases the rate of fuel input. The supporting member 24 is preferably adjustable manually so that the lever 2l maybe 'rocked independently of the bellows to which it is attached to manually regulate the rate of fuel feed. For manual adjustment the member 2l may carried by a nut 25 rotatably mounted in a fixed support, so that by turning the nut 25 suresensitive control devices in-:Vbrder to climi.- nate' connecting linkages or in order to provide v control elements. of differing pressure-'sensitive the pivot 23 of the'lever 2l may be shifted to rock the lever 2| about its connection to the bellows i3 and thereby actuate the regulator 20. Also, by adjusting the pivot 23, the fuel charge may be made leaner or richer throughoutl the range ofv the automatic control.

The fuel pump I3 is a.- piston pump such as commonly used for. injecting measured quantities of fuel into engine cylinders, in which the amount of fuel delivered upon each stroke .ofthe piston is controlled by a bypass controlled by the regulator 2p. As shown in Fig. 4, the pump may have a lateral fuel inlet Ita and a piston 26- which closes the inlet during'the pressure stroke. The bypass, which is not fully shown herein, may

include a helical groovek 23a on the piston 23 and y the volume of lfuel discharged may be controlled by turning the piston -26 about its axis. 'I'he regulator 20 may be in the form of a rack meshing' with an elongated gear-'formed on the piston 26 so that anaxial movement of the regulator will impart a turning movement to the pisto'n adcharacteristics. In Fig. 25ct the drawings-theonlet and exhaust controlling valves-are shown connected to a single pressure-sensitive actuator. In Fig. 3 of the drawings-the inlet controlling valve, the. exhaust controlling valve, the air pump speed control, andthe fuel regulator are shown connected to separate pressure-'sensitive actuators. In Flg.5 of the drawings the exhaust throttling valve and the fuel `feedregulator are shownconnected to one pressure-sensitive actuator," and the inlet controlling valveis shown connected .to a separate pressure-sensitive actu-'- ator. VIn. Fig. 6 of the drawings the inletand i exhaust controlling valve, the air pump speed control, and the fuel -feed regulator areshown operatively connected tive actuator. l Y

In supercharged'- engines -where the inlet lis throttled at sea level, I prefer-Ato s'o control the deliverypump I3 that it will deliverfuel at a constant rate up to a certain altitude'. and at a stant pressure of air lmay be maintained up to justing the helical bypass groove `26a to permit more or less of the trappedfluid to escape through the bypass. The piston is operated by a timer shaft 21 driven bythe engine which has a cam 28 which actuates the piston to deliver charges of fuel Athrough the pipe I9 tol the engine cylinder at intervalsproperly timed with respect to the movements of the engine pistons.

Inasmu'ch as the fuel pump per se is old and well known, only enough of the pump is shown to make clear the operation of the control device of.

the present invention.

In order to maintain the power of the engine throughout a `greater range ofaltitudes it is desirable'to provide means forI automatically increasing the speedof'the airpump as the altitude of night is increased'.

As shown in Figs. 3 and' 13, pump 3 may be regulated bya bellows I3c. l Any the speed of the ai-r" varying rate above the predetermined altitude. Such an arrangement is desirable because a cona certain predetermined altitude-and above that altitude-there is a reduction in the yamount of suitable Vchange speed device may be-employed by which the speed of rotation of the pump 9l lmay be increased automatically upon a reducl tion in atmospheric pressure due to.- an increase in the altitude of the aircraft on which the engine is mounted. In` Fig. 13 there is shown a change speed device` of va well known type in which the pump shaft 3a and a driven shaft 3b Vhave disks 9c and 9d provided with opposed concave toroidal surfaces engaged by friction rollers 9e which are freely rotatable and mounted upon fixed trunnions, the roller supports are connected by a link 3f to cause the supports to turn in opposite directions, and one of the supports has anfarm 9g connected to the movable head of. the bellows llc. The peripheries-of the rollers 9e are spherical .and conform to the driving surfaces on the disks 3c and 3d. Upon expansionof the bellows the rollers move out on the disk 3d and inwardly on the disk 9c, thereby increasing the speed of rotation of the pump 8.

'The inlet and exhaust controlling valves and the fuel regulator may be controlled. by a single.

' pressure-sensitive device orby individual pres- ,sure-sensitive devices, or any two of the'controlling elements may be connected to a single pressure-sensitive device. In some instances'it may beadvantageous to provide separate .presair delivered to the cylinder, 'Y and it is, therefore,

desirable to effect a proportional reduction-in the' ControllingI .means for eecting` fuel charge. regulation of the fuel feed only above a lpredetermined altitude i s shown in Fig. 6 of the drawings,l

in which the inlet controlling valve I3 and the exhaust vcontrol-ling valve I2 are simultaneously operated through connecting rods I5 and I6 by a single pressure-controlled power actuated operating device il. The fuel'regulator 20 is in this 'instance connected by a link-29 to a lever 30 which swings about a pivot 3l.. A spring 32 normally holds the lever in engagementwit'h an adjustable stop member 33 which may be in the form of a screw, 'the tension of the spring 32. I tending to rock the lever 3l`in a direction to engage the lever with the stop screw 33l andv to hold'the lever-in the'position determined bythe adjustment of the screw 33. Means is preferably provided for actuating the lever.3|lman.. ually to shift the regulator 20 so -that the rate' of fuel feed may be regulated independently of the automatic control. To provide for manual control of the fuel regulator the pivot 3l maybe carried bya screw 34 `which maybeadju'sted manually by means of a nut 34a to adjust the lever 30. l

` The blowerspeed'control device may also .be

actuated by the operating device Il by connecting the arm`3g' of the speedcontroly device to the actuating rod .I6 by means of a'link I Ga.

The operatingdevice I'lhas a movable fhead 35 which is engageable 'with a projection 35 carried by the lever-30 at the endthereof oppo' site that connected to the vregulator 2Q, The

lever'30 normally engages the stop screw 33 and the projection 3B `is-off'set 'Withre'spec't to thev head 35-when the head 35 is in its retracted position,' so that the head 35- has a predetermined amount oi outward movement before it engages lwith the projection .33.. During the movement of the head 35 prior to engagement vwith the projection 35 of the lever 30, the inlet and exv f.haust valves [tand I2 are actuated while the' w fuel..regulator remainsin anxed position. By

adjusting the screw 33 the extent of free moveto 'a single pressure-sensiment of the head 35 may be regulated so that a predetermined reduction inatmospheric pressure corresponding to the pressure at a predetermined altitude will be required to move the head 35 into engagement withvthe projection 36 of the lever. The head 35 of the operating member |1 moves outwardly as the altitude of the air. craft increases and atmospheric pressure decreases, gradually opening the inlet valve I and simultaneously moving the valve I2 toward closed position to throttle the exhaust. After the predetermined altitude is reached, the head will engage with the projection 36 of the lever 30, causing the fuel feed regulator 28 to be actuated to gradually reduce the rate of fuel input, on further decrease in atmospheric pressure as the aircraft moves to higher altitudes.

'Ihe pressure-sensitive power actuated operating member l1 is illustrated in detail in Fig. 7 of the drawings. A power actuated operating member may be desirable in connection with large engines or where asingle actuator is provided for several valves and fuel feed regulators. For example, it may be desirable in multi-engine air craft to connect the control elements of all the engines to a single pressure-sensitive actuator. In this device the pressure-sensitive element is in the form of a bellows 31 mounted within and at one end of a casing 38 which may be of cylindrical form. The bellows 31 is subjected to atmospheric pressure and a spring 33 may be provided within the bellows to act in opposition to atmospheric pressure. A passage may be provided inthe end ofthe casing 38, to which the bellows is attached, through which air may Ibe exhausted from the interior of the bellows. After exhausting the bellows the pas'- sage 40 may be plugged so that the bellows will be sensitive to variations in pressure of the atmosphere. The movable end of the bellows 31 is attached to a plunger 4|. 'Ihe plunger 4| Ahas a sliding fit in an axial borein a piston 42 which is mounted for sliding movement within the outer portion of the casing 38. Intermediate its ends the casing 38'is provided with a partition 43 and its outer end is closed by a head 44. The piston 42 has an inwardly projecting sleeve 45 which ts slidably within a central aperture in the partition 43 and has an outwardly projecting sleeve 46 which is slidable in a central aperture in the head 44. 'I'he sleeve 46 has a closed end 41 which carries the actuating head 35 and which is connected to the valve actuating rod |5. 'I'he partition 43 provides a bellows chamber 48 at the inner end of the casing 88 and atmospheric pressure is maintained within the bellows chamber by means of one or more openings 48 to the atmosphere. To permit relative movement between the plunger 4| and piston 42 the outer end of the plunger 4| is spaced from the closed end 41 of the piston forming a chamber 50 within the outer end of the piston. It is desirable that the pistonv be freely movable with respect to the plunger 4|, and means is, therefore, provided for equalizing the pressure in the chambers 48 and 58. An axial passage 5|, extending from the outer end of the plunger 4| to a diametrical passage 52 within the chamber 48, maintains constant communication between the chambers 48 and 58 and serves to equalize the pressure nsaid chambers 48 and 58. 'I'he piston 42 is power actuated and its movement is controlled by the bellows 31, as will be presently explained. Motive power for actuating the piston 42 may be supplied by oil under pressure delivered from the engine lubricating system. This oil may be delivered to the piston chamber of the casing 38 through a pipe 53 which com municates with a wide groove 54'in the periphery of the piston 42. The groove 54 communicates through a radial passage 55 in the piston with a circumferential groove 56 formed on the plunger` 4|. 'Ihe circumferential groove 56 communicates through a radial passage 51 with an axial passage 58 formed in the plunger 4|. 'I'he axial passage 58 communicates at its opposite ends with radial passages 59 vand 60 which lead to circumferential grooves 6| and 62 formed on the plunger 4|, the groove 6| being within the sleeve portion 45 of the plunger and the groove 62 ,being within the sleeve portion.46 of the plunger. 'I'he plunger 4| is provided a short distance outwardly of the circumferential groove 6| with a circumferential groove 63 which communicates through a radial passage 64 with the axial passage 5| of the plunger. A short distance inwardly of the groove 62 the plunger is provided with a circumferential groove 65 which communicates through a radial passage 66 with the axial passage 5|. The sleeve 45 is provided with apertures 61 which are normally positioned between the grooves 6| and 63, and these apertures are adapted to establish communication between either the groove 6| or the groove 63 and the inner pressure chamber 68 between the partition 43 and the piston 42 upon an outward or inward movement of the plunger 4| with respect to the piston 42. Apertures 68 are provided in the sleeve 46. These apertures are normally positioned between the grooves 62 and 65 so as to establish communication between the outer pressure chamber 10 between the -piston 42 and the head 44 and the groove 62 or the groove 65 upon an inward or outward movement of the plunger 4| with respect to the piston. A suitable packing ring 1| may be provided to seal the opening of the head 44 and a. drain outlet 12 is provided at the bottom of the chamber 48 to carry away oil exhausted from the pressure chambers 68 and 10.

In the operation of the device, oil under pressure is maintained in the piston groove 54, the plunger groove 56, and the axial passage 58 of the plunger. The openings 61 and 68 leading to the pressure chambers 68 and 10 are normally covered by the cylindrical portions of the plunger 4| between the grooves 6| and 63 and 62 and 66. Upon a drop in atmospheric pressure, the plunger 4I is moved outwardly by the spring 38, causing the groove 6| to register with the openings 61 and the groove 65 to register with the openings 68. Oil under pressure is admitted to the chamber 68 from the groove 6| through the openings 61, creating `pressure in the chamber 66, tending to move the piston 42 outwardly. At the same time, oil is permitted to escape from the chamber 16 through the apertures 68 into the groove 65 through the radial-passage 66 into the axial passage 5| of the plunger 4I into the chamber 48, and to the drain outlet 12. Pressure of the oil in chamber 68 moves the piston 42 outwardly, and this movement continues until the apertures 61 and 66 are moved out of register with the grooves 6| and 65. Thus, upon an outward movement of the plunger 4| due to a decrease in atmospheric pressure, a corresponding movement is imparted by the oil under pressure to the piston 42 which actuates the valves and fuel regulator.

Upon an inward movement 'of the plunge:` 4I

4atoms? due to an increase in atmospheric pressure, such as'that d'ue'to movement from a' high altitude to a lower altitude, fluid under pressure is-admitted to the chamber'10 from the groove 82 and oil is drained from' the chamber 88 through theapertures 61, groove`83, and passage 5|, causing an inward movement of the plunger 4|. Byproviding a power actuated member and controlling the movement ofthe power actuated member byl means of a pressure-sensitive element, any desired amount of force may be exerted upon the In Figs. 8 to 11,of the drawings there is shown actuator in which thebperating element has a turning movement instead of anaxial movement.

' valvesand fuel regulating devices to actuate the same.

'a modified form of air pressurel controlled power In this modification the movable-operating meni-v e ber is a shaft .80,which has an arm 8| connected to the valve actuatingrod |5. 'I'he shaft 80 is mounted in a casing 82 which has end bearing portions 83 and 84 andan enlarged cylindrical chamber portion 85. `The shaft 80 has an` enlarged portion 88jwithin the enlarged portion 85 of the" casing. the `opposite ends of which are` l journaled in the end bearing portions 83 and 84 ing which leads to a circumferential groove |02 around the shaft 90. The groove |02 opens to lfour longitudinal grooves |03 in the shaft 90, the

grooves |03 being arranged in-two pairs which are on diametrically opposite sides of the shaft. The exhaust pipe connects with a passage |04 in the bearing portion 84 of the casing which leads to a circumferential groove around the shaft 90 which is connected by radial passages |06 with an axial passage |01 leading to the ini ner end of the shaft 90. Radial passages |08 yextend from the passage |01 to the periphery of the shaft 90 between the longitudinal grooves |03 of each pair. The enlarged portion 86 of the shaft 89 has passages |09 and ||0 on opposite sides of and adjacent to each of the vanes 98 through which communication may be established of a pressure-sensitive device such as a bellows 92..V The shaft 80 isactuated by fluid pressure within the casing 82 and to prevent leakage of fluid from the casing, packing glands 93 and 94 are provided around the shafts 80 and 90 in the bearing portions 83 and, 84 of Ithe casing 82. The shaft 90 is held against endwise movement and between the pressure chambers of the casing and the passages within the bore 89.

The shaft 90 is normally so positioned that t the outer ends of the passages |08 are closed by the portion of the wall of the bore 89 lying between the passages |09 and ||0 and the passages |09 -a'nd ||0 are closedby the cylindrical portion of the surface of the shaft 90 lying between the grooves |03 and the passages |08, as shown in Fig. 10. If the shaft 90 be turned in a clockwise direction from that shown in Fig. 10,

is permitted a limited turning movement with respect to the shaft 80 by means of radial splines 95 which extend into -arcuate slots in the endof the 'shaft so which engages the .shomderss or the casing. The splines 95 project outwardly into arcuate slots 98 in the end of the enlarged portion 86 of the'shaft 80 and bear against the shoulder 88. The slots 98are wider than the splines 95 and Vpermit the shaft 90 to have a 4limited turning movement with respect to the shaft 80.

The enlarged portion 85 of the casing has inwardly extending partition walls 91 on opposite sides of the shaft 80 which bearat their edges on the enlarged portion 8.8 of the shaft 80 and two separate chambers. The. enlarged portion 88 of the shaft 80 carries two diametrically opposite vanes 98 which bear against the interior of -the posite side of the vane, turning movements may be imparted to the shaft 80. Fluid under pressure, such as oil from the engine lubricating system, may be conducted to the casing 82 by means of a pipe 99' connevcted to the bearing portion 84 r and exhausted from the casing through a drain pipe |00. The pressure line 99 connects with 'a passage |0| in the bearing portion 84 of the casdivide the cylindrical portion 95 of the. casing into cylindricalwall of the casing, one of the vanes 75, sensitive to variations in atmospheric pressure,

the passages |09 .11 be registered with grooves |03 and the passages ||0 will be registered with the passages |08 so that pressure is admitted to the chambers on one side of the vries 98 and exhausted from the chambers at the opposite sides of the varies, applying pressure to the vanes in a, direction to turn the shaft 00 in a clockwise direction. A turning movement of the shaft 90 in a counterclockwise direction will connect the passages .||0 withthe grooves |03 and the passages |09 with the passages |08 to .impart a counterclockwise movement to the shaft 80. In

operation small angular movements are imparted to the shaft 9|)y by the bellows 92 and similar movements are imparted by fluid pressure to the shaft 80, the movement of.l the shaft in each case being just suflicient to move the passages |09 and ||0 to non-registering position, so that the angular movements imparted to the shaft 80 by the fluid under pressure are always approximately equal to the angular movements imparted to the shaft 9i). The arm 8|, being connected to an engine controlling element, will impart a movement to that element proportional to the movement of the pressure-sensitive device actuating the shaft 90. If the oil pressure should fail, the bellows 92v would impart the necessary motion to the shaft 80 through the splines 95.

In either of the power actuated control devices herein shown the movement` of the power .actuated member is equal to themovement of a carried by an aeroplane ||3. The inlet pipe 8.

and exhaust pipe Il are connected to suitable manifolds ||4 and ||5 which communicate with the engine cylinders. The inlet and exhaust valves |0 and l2 may be controlled by suitable actuating devices such as I3 and` |3a which are so that the controlling valves are automatically .A without departingr from my invention as defined in the appended claims.

What I claim is:

1. In a two-stroke cycle engine for` aircraft, a cylinder providedwith inlet and exhaust passages, a valve for throttling the exhaust, a valve for throttling the inlet, and means automatically responsive to variations in altitude for simultaneously adjusting said valves, one toward open and the other toward closed position.

2. In a two-stroke cycle engine for aircraft, a'cylinder having inlet and exhaust passages, a valve for throttling the exhaust, a -valve for throttling the inlet, fuel feeding means, and means responsive to variations in atmospheric pressure for moving said exhaust throttling valve toward closed position and said inlet throttling valve toward open position upon a decrease in atmospheric pressure and for simultaneously controlling said fuel feeding means to increase the fuel input.

3. In a two-stroke cycle engine for aircraft, a cylinder having inlet and exhaust passages, means for delivering air` under pressure to-the cylinder inlet, a valve for throttling the exhaust, a valve for throttling the inlet, and means automatically controlled by variations in atmospheric pressure for moving said exhaust throttling valve toward closed position and said inlet throttling valve toward open position upon a decrease in atmospheric pressure.

4. In a two-stroke cycle engine for aircraft, a cylinder having inletand exhaust passages,

means for delivering air under pressure to thev cylinder inlet, a valve for throttling the exhaust, a valve for throttling the inlet, fuel feeding means including a fuel pump, and means responsive to variations in atmospheric pressure for actuating said valves, one toward open position and the other toward closed position and for simultaneously controlling said pump 'to vary the rate of fuel delivery.

5. In a two-stroke cycle engine for aircraft, a cylinder having inlet and exhaust passages, means for delivering air under pressure to the cylinder inlet, a valve for throttling the exhaust, a valve for throttling Athe inlet, fuel feeding means including a fuel pump, means responsive to variations in atmospheric pressure for actuating said valves and for simultaneously controlling said pump to vary the rate of fuel de livery,. and independent means for controlling the delivery of said pump.

6. In a two-stroke cycle/engine for aircraft, a-cylinder provided with inlet and exhaust passages, meansl for delivering air under pressure to the inlet, a bellows adapted to expand and contract as the atmospheric pressure decreases or increases, and means opera'fdgby the bellows for simultaneo ly throttling fh fexhaust and controlling sai air delivering means to increase the rate of flow of air to the'.` cylinder upon expansion of the bellows.

' 7. In a two-stroke cycle engine for aircraft,

a cylinder provided with inlet and exhaust passages, means for delivering air under pressure to the inlet, a bellows adapted to expand and contract as the atmospheric pressure decreases or increases, means operated by the bellows for simultaneously throttling the exhaust and controlling said air delivering means to increase the rate of flow of air to the cylinder upon expansion of the bellows, means for feeding fuel to the cylinder, and means controlled by said bellows for regulating the rate of fuel feed.

8. In a two-stroke cycle engine for aircraft,.

a cylinder provided with inlet and exhaust passages, means for delivering air under pressure to the inlet, a bellows adapted to expand and contract as the atmospheric pressure decreases or increases, means operated by the bellows for simultaneously throttling the exhaust and controlling said air vdelivering means to increase the rate of flow of air to the cylinder upon expansion of the bellows, means for feeding fuel to the cylinder, means controlled by said bellows for regulating the rate of fuel feed, and independent means for regulating the fuel feed.

9. In a two-stroke cycle engine for aircraft, a cylinder provided with inlet and exhaust passages, means for delivering air under pressure to the inlet, a bellows adapted to expand and con- .tract as the atmospheric pressure decreases or increases, means operated by the bellows for simultaneously throttling the exhaust and controlling said air delivering means to increase the rate of flow of air to the cylinder upon expansion of the bellows, means including a fuel pump for feeding fuel to said cylinder, and means operated by said bellows for controlling the rate of delivery of fuel from said pump to said cylinder.

10. In a two-stroke cycle yengine for aircraft, a cylinder provided with inlet and exhaust passages, means for delivering air under pressure to the inlet, a bellows adapted to expand and contract as the atmospheric pressure decreases or increases, a spring acting upon said bellows and tending to expand the same in opposition to the atmospheric pressure, and means operated by said bellows for simultaneously throttling the exhaust and controlling the air delivering means to `increase the rate of delivery of air to the vcylinder upon a decrease in atmospheric pressure.

1l. In a two-stroke cycle engine for aircraft, a cylinder having inlet and exhaust passages, means for delivering air to the inlet passage, fuel feeding means adapted to normally deliver a predetermined charge of fuel to said cylinder,

pressure for throttling the exhaust and controlling the air delivering means to increase the volume of air delivered to the cylinder upon a decrease in atmospheric pressure and for controlling the fuel feeding means to Vary the fuel chargeV when the variation from normal atmospheric pressure exceeds a predetermined amount.

12. In a two-stroke cycle engine for aircraft, a cylinder having inlet and exhaust passages, means adapted to normally deliver a predetermined charge of fuel to said cylinder, an element sensitive to variations in atmospheric pressure, and means controlled by said pressuresensitive element at atmospheric pressures below a predetermined pressure lower than normal atmospheric pressure fo;` effecting an adjustment of the fuel feeding means to vary the fuel charge, said adjusting means being unaffected by said pressure sensitive element at pressures above'said predetermined pressure.

13. In a two-stroke cycle engine for aircraft,

a cylinder having inlet and exhaust passages,

posed with respect to said pressure-sensitive means that said actuating means is unaffected by said pressure-sensitive means throughout a predetermined range of atmospheric pressures but is responsive to variations beyond said range.

14. In a two-stroke cycle engine for aircraft, a cylinder having inlet and exhaust passages, means adapted to normally deliver apredetermined charge of fuel to said cylinder, an element sensitive to variations in atmospheric pressure, fuel feed regulating means for varying ,the fuel charge, actuating means interposed between said pressure-sensitive means and said regulating means, said actuating means being so disposed with respect to said pressure-sensitive means that said actuating means is unaffected by said pressure-sensitive means throughout a predetermined range of atmospheric pressures but is responsive to variations beyond said range, and means for effecting a relative adjustment of said pressure-sensitive means and said actuating means to vary the extent of the range of atmospheric pressures to which said actuating. means is unresponsive".

15. In a two-stroke cycle engine for aircraft, a cylinder having inlet and exhaust passages, means adapted to normally deliver apredetermined charge of fuel to said cylinder, an element sensitive to variations in atmospheric pressure,

-means controlled by said pressure-sensitive element for effecting an adjustment of the fuel feeding means to vary the fuel charge `upon a predetermined variation in atmospheric pressure, and independent means for regulating the quantity of fuel delivered to the cylinder.

16. In a two-stroke cycle engine for aircraft, a cylinder having inlet and exhaust passages, means adapted to normally deliver a predetermined charge of fuel to said cylinder, an element sensitive to variations in atmospheric pressure, fuel feed regulating means for varying the fuel charge, actuating meansinterposed between said pressure-sensitive means and said regulating means, said actuating means being so disposed with respect to said pressure-sensitive means that said actuating means is unaiected 'by' said pressure-sensitive means throughout a predetermined range of atmospheric pressures but is responsive to variations beyond said range, and means controlled by said pressure-sensitive means for simultaneously throttling the exhaust and increasing the volume of air delivered to the cylinder upon a decrease in atmospheric pressure.

17. In a two-stroke cycle engine for aircraft, a cylinder provided 'with inlet and exhaust pas-` sages, a bellows adapted to be expanded and contracted by variations in atmospheric pressure, a movable actuating member controlled by said bellows,.means operated by said actuating mempredetermined i movement of said actuating i member. i

18. In a two-stroke cycle engine for aircraft, a cylinder provided with inletand exhaust passages, a bellows adapted to be expanded and contracted by variations in atmospheric pressure, a movable actuating member controlled by said bellows, means operated by said actuating member for throttling or unthrottling t'ie exhaust and simultaneously unthrottling or throttling the inlet upon 'a decrease or increase of i atmospheric pressure, fuel feeding means, regulating means for said fuel feeding means including a pivoted member positioned1 to be actuated by said movable actuating member after a predetermined movement of said actuating member, and means for adjustingsaid pivoted member relatively to said actuating member to vary the extent of movement of the actuating member independently of the pivoted member.

19. In a two-stroke cycle engine for aircraft, a cylinder provided with inlet and exhaust passages, a bellows adapted to be expanded and contracted by variations in atmospheric pressure, a

movable actuating member controlled by said bellows, means operated by said actuating member for throttling or unthrottling the exhaust and simultaneously unthrottling or throttling the inlet upon a decrease or increase of atmospheric pressure, fuel feeding means, regulating means for said fuel feeding means, including a pivoted member positioned to be actuated by said movable actuating member after a predetermined movement of said actuating member, and independent meansito vary the rate of fuel feed.

20. In a two-stroke cycle engine for aircraft, a

cylinder provided with inlet and exhaust passages, means for delivering air under pressure to the inlet, a bellows adapted to be` expanded or contracted by a decrease or increase in atmospheric pressure, means controlled by said bellows to throttle or` unthrottle the exhaust upon a decrease or an increase of atmospheric pressure, a second bellows, and means controlled by said second bellows to unthrottle or throttle the inlet upon a decrease or an increase of atloer` for throttling or unthrottling the exhaust cluding a pivoted memberpositioned to be lactuated by said movable actuating member after av mospheric pressure.

2l. In-a two-stroke cycle engine for aircraft, a cylinder provided vwith inlet andexhaust passages, means for delivering air under pressure to the inlet, a bellows adapted to be expanded or contracted by a decrease or increase in atmosp heric pressure, means controlled by said bellows to throttle or unthrottle the exhaust upon a decrease or anfincrease of atmospheric pressure, a second bellows, means controlled by said second bellows to unthrottle or throttle the' inlet upon a decrease or an increase of atmospheric pressure, fuel' feeding means, and means controlled by the rst mentioned bellows' to regulate the fuel 'feeding means.

22. In a two-stroke cycle engine for aircraft, a cylinder provided with `inlet and exhaust passages, means for delivering air under pressure to the inlet,'a bellows adapted to' be expanded or contracted by a decrease or increase in atmospheric pressure, means controlled by said bellows to throttle or unthrottle the exhaust upon a decrease or an increasev of atmospheric pressure, a second bellows, means controlled by said second bellows to unthrottle orthrottle the inlet upon a. decrease or an increase of atmospheric pressure, fuel feeding means, althird bellows,`and

23. In a two-stroke cycle engine for aircraft, a cylinder provided with` inlet and exhaust passages, a power actuated member, means actuated by said member for throttling or unthrottling the exhaust, a bellows having a part movable in response to variations in atmospheric pressure, a spring acting upon the movable part of said bellows in opposition to the atmospheric pressure, and means for controlling the movements of the power actuated member by the movements of the bellows. 1

24. In a two-stroke cycle engine for aircraft, a cylinder provided with inlet and exhaust passages, a power actuated member, means actuated by said member for throttling or unthrottling the exhaust, means operated by said power actuated member for unthrottling or thr'ottling` the inlet simultanebusly with the throttling or unthrottling of the exhaust, and means responsive to changes in altitude for controlling the movements of said power actuated member.

25. In a two-stroke cycle engine for aircraft,

a cylinder provided with inlet and exhaust passages, a power actuated member, means actuated by said member for throttling or unthrottling the exhaust, means operated by said power actuated member for unthrottling or throttling the inlet simultaneously with the throttling or unthrottling of the exhaust, fuel feeding means, means op erated by said power actuated member for regulating the rate of fuel feed, and pressuresensi tive means responsive tochanges in atmospheric pressure for controlling themovements of said power actuated member. f

26. In a two-stroke cycle engine for aircraft, a pump for supplying air under pressure to the engine cylinders, an exhaust throttling valve, and means automatically responsive to variations in altitude for simultaneously actuating said valve and varying the speed of said air pump. 27. In a two-stroke cycle engine for aircraft, a pump for supplying air under pressure to the engine cylinders, fuel feeding means, pressure sensitive actuating means, and means operated by said pressure sensitive means for simultaneously varying the rate of fuel .feed and the speed of said air pump. v

28. In a two-stroke cycle direct fuel injection engine for aircraft, a pump for supplying air under pressure to the engine cylinders independently of the fuel, means including a change speed mechanism for driving said pump, a pressure' sensitive actuator, and means connecting said actuator to said change speed mechanism to automatically vary the speed of said pump in accordance with variations in atmospheric pressure.

29. In combination with an internal combustion engine for aircraft, means for supplying combustible charges to the engine cylinders vcomprising fuel feeding means and a pump' for supplying air under pressure to the engine cylinders including a speed changing device, fuel feed regulating means, and means responsive to variations in atmospheric pressure for controlling said speed changing device and said fuel feed regulating means.

HERACLIO ALFARO. 

